The 19-year-old former captain of Tyrone GAA's minor footballers, admits shooting his father but denies murder him on the grounds of diminished responsibility.The issue being contested is the teenager's mental state when he killed his father in January 2013.Aloysius Hackett, 60, was shot twice in the head outside his home near Augher.Defence lawyers have argued that Sean Hackett was suffering from a mental health condition at the time and was unable to form rational judgements.They say he had depression and possibly displayed the early stages of schizophrenia.However, this has been rejected by prosecution lawyers.At Dungannon Crown Court on Tuesday they called evidence from forensic psychiatrist Dr Fred Browne, who said Sean Hackett did not have depression or any other mental health condition.Dr Browne told the jury the killing was not carried out in a rage and he said: "Having interviewed him (Sean Hackett) recently I did not feel there was evidence of schizophrenia."With the evidence now finished in the trial, prosecution and defence counsel are preparing to make closing speeches to the jury on Wednesday.